DIRECT DETERMINATION OF THE METASTABLE LIQUID MISCIBILITY GAP IN UNDERCOOLED CU-CO ALLOYS

Bulk Cu-Co alloys at compositions ranging from 10 to 80 wt.% Co were h ighly undercooled using a melt fluxing technique. The metastable liqui d separation boundary has been directly determined from the measured t emperature-time profiles. It was also calculated using a subregular so lution model. The critical point of the miscibility gap was found to b e about 80 K below the Liquidus. A droplet-shaped microstructure was o bserved for all solidified specimens (Cu-10 to 80 wt.% Co), when the m elts were undercooled into the metastable miscibility boundary. (C) 19 98 Elsevier Science B.V. All rights reserved.